Battery terminals are typically cold formed or die cast from lead or lead alloys. In a conventional battery, the terminals protrude from a casing or container which carries electrolyte. The container is typically formed from a moldable thermoplastic resin, such as polypropylene. During manufacture of the container, the resin flows around the base of the terminals so that the resin will secure the terminals in place once it hardens. After a terminal has been secured, a lead anode can be inserted into a central hole in the terminal and melted to fill the hole and form a mechanical and electrical connection to a battery grid positioned within the container.
Battery terminals can include annular acid rings that extend around the base of the terminal to provide an extended interface between the base of the terminal and the adjacent container material. This interface can provide a torturous path or “labyrinth seal” that inhibits or prevents electrolyte from escaping the battery container. Various types of terminal seals, and methods for making such seals are disclosed in U.S. Pat. No. 7,338,539, titled “Die Cast Battery Terminal and Method of Making Same,” filed Mar. 4, 2004, and U.S. Patent Application Publication No. 2005/0147882, titled “Battery Part,” filed Dec. 3, 2004, each of which are incorporated into the present application in their entireties by reference. Conventional battery terminals may become loose in the container wall if subjected to repeated or excessive twisting or torsional loads. Additionally, shrinkage of the battery container may also contribute to loosening of conventional terminals over time.